Deposition and characteristics of chromium nitride thin film coatings on precision balls for tribological applications

Thin film hard coatings on rolling element surfaces can enhance the overall wear resistance of rolling element bearings, as demonstrated previously for coated tapered, cylindrical, and spherical roller bearings. Hard coatings in ball bearings are less common because of the difficulty in achieving uniform film thickness on a ball surface. This limitation is overcome by a new process for depositing chromium nitride coatings with uniform thickness on precision balls using ion beam assisted deposition (IBAD) e-beam evaporation. Scanning electron microscopy indicated that the deposited films were smooth and conformal on the ball surfaces with no areas of localized delamination. Auger electron spectroscopy confirmed that Cr₂N and CrN bulk film stoichiometry was achievable by modulating the argon to nitrogen process gas ratio during deposition. Transmission electron microscopy revealed dense, polycrystalline film structure. Film hardness and elastic modulus as measured using nanoindentation on the coated balls met expectations for chromium nitride, and tribological testing of the coated balls in angular contact ball bearings under moderate contact stress levels demonstrated adequate film adhesion for practical use of these coatings in bearing applications.     

Surface modification of silicone rubber by ion beam assisted deposition (IBAD) for improved biocompatibility

We studied the preparation of antimicrobial silicone rubbers of improved interfacial strength, which could be formed with the ion beam assisted deposition (IBAD) technique for coating metallic or inorganic materials (silver (Ag), Copper (Cu), and Hydroxyapatite(HAp)/TiO₂) on the silicone surface. Those coating materials provide high product safety as well as outstanding antimicrobial activity. The deposition methodology is composed of pre‐etching with oxygen gas, vaporizing the coating materials, and post‐treatment with Ar ion. With the evaporation of the coating materials, the Ar beam was focused on the substrate to assist deposition. It was found out that the ion assisting depositions in the IBAD process give a prominent enhancement in adhesion between silicone rubbers and coatings of Ag and Cu. The HAp/TiO₂ coating layer was easily dissolved in aqueous saline solution. All deposited layers display high antimicrobial activities against Staphlococcus aureus (ATCC 6538) and Escherichia coil (ATCC 25,922), showing 99.9% reduction of bacteria, respectively. In a cytotoxicity test, the Ag and HAp/TiO₂ coated silicone shows a decrease of cytotoxicity, while the Cu coating leads to a slight increase of cytotoxicity. The result on the surface modifications of silicone rubber will be employed in further study for applications of medical or rehabilitation devices. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1095–1101, 2005     

p-type conductive NiOx: Cu thin films with high carrier mobility deposited by ion beam assisted deposition

Transparent conductive NiO thin films with 18 at% Cu dopant were fabricated by ion beam assisted deposition (IBAD). Their structural and optoelectronic properties were compared with undoped NiO films and NiO films doped with 12 at% Cu, and also compared with NiO:Cu (18 at%) films deposited by RF sputtering as reported in our previous work. The results show that the crystallinity of NiO thin films deposited through IBAD technology is much better than that of the films deposited by RF sputtering. Thanks to this reason, the highest carrier mobility above 45 cm²V^?1s^?1 for NiO:Cu (18 at%) film can be realized here. Meanwhile, the films’ resistivity remains an acceptable value, varying from 2.05 to 0.064 Ω cm with oxygen ion beam current changing from 0.2 to 0.8 A. This feature is imperative for p-type transparent conductive oxides (TCOs) applied in various domains. In addition, with oxygen ion beam current increase, the increase of the Ni³⁺/Ni²⁺ ratio leads to more Ni²⁺ vacancies be introduced into NiO films, which is beneficial to generate holes and improve carrier concentration. In this work, the optimal carrier mobility of NiO film doped with 18 at% Cu is obtained when the oxygen ion beam current is 0.2 A. Its carrier concentration and electrical resistivity are 7.26 $\times$10¹⁶ cm^?3 and 2.05 Ω cm, respectively.     

高能离子束辅助沉积制备钛纳米膜

用离子束溅射沉积和高能离子束辅助沉积方法制备了具有择尤性的钛纳米薄膜，并采用原子力显微镜、X射线衍射仪和俄歇电子谱仪研究了试样表面预处理、离子束流和温度等离子束工艺参数对钛薄膜结构的影响。结果表明：离子束溅射沉积的钛膜在[002]和[102]晶向上呈现出明显的择尤生长现象，并分别在该两个晶向上表现出纳米晶型和非纳米晶型结构；当用高能离子束辅助沉积时，[102]晶向择尤生长现象消失，且钛膜的结构对束流变化较为敏感，束流较低时，钛膜为纳米结构且择尤生长现象减弱，而束流增加时晶粒长大，择尤生长现象叉增强。另外钛膜容易受到氧的污染，并随辅助离子强度增加而增强。     

Al_2O_3陶瓷基片沉积钼膜的织构研究

采用蒸镀、离子束辅助沉积（IBAD）技术，在Al2O3（单晶、多晶）和玻璃基片上沉积钼膜，通过XRD，TEM等分析手段对于钼膜的织构及其产生机理进行了探讨。结果表明：在单晶和多晶A2O3以及非晶态玻璃基片上蒸镀的钼膜均存在强（110）织构。对于IBAD薄膜，随着氩离子轰击能量的增加，（110）织构向（200）织构转变。膜内应力计算及TEM观察结果证实，钼膜发生了塑性流变，而且塑性流变具有不均匀性。塑性流变的结果使得钼膜产生了（110）织构。     

霍尔无栅离子源的研制及应用

基于离子束辅助镀膜技术,自主研制了一款新型霍尔无栅离子源,利用该离子源,采取离子束辅助沉积方法,在玻璃基底上镀制了多种光学薄膜,并对所镀制光学薄膜的性能进行了测试。测试结果表明:所研制的霍尔无栅离子源制备的各种光学薄膜,其膜层强度、附着性、耐腐蚀性以及光学性质都比常规热蒸发工艺所制得的薄膜有明显改善。     

Tribological Properties of DLC Film Prepared by C ^＋ Ion Beam-assisted Deposition （IBAD）

C ^＋ ion beam-assisted deposition was utilized to prepare deposit diamond-like carbon （ DLC ） film. With the help of a series of experiments such as Raman spectroscopy, FT-IR spectroscopy, AFM and nanoindentation , the DLC film has been recognized as hydrogenated DLC film and its tribologicul properties have been evaluated. The bull-on-disc testing results show that the hardness and the tribologicul properties of the DLC film produced by C^ ＋ ion beam- assisted deposition are improved significantly. DLC film produced by C ^＋ ion beam- assisted deposition is positive to have a prosperous tribologicul application in the near future.     

Synthesis of nanoscale multilayered ZrN/W coatings by ion beam assisted deposition

ZrN/W multilayered coatings with different modulation periods at the nanoscale have been synthesized at different N+ beam bombarding energies using IBAD. Various characterization techniques such as XRD, AES, nano indenter and profiler were employed to investigate the influence of modulation period and bombarding energy on microstructure and mechanical properties of the coatings. The results showed that all superlattice coatings had better mechanical properties than the monolithic ZrN and W coatings. At an optimal condition with 300 eV N+ beam bombarding energy and 8―9 nm modulation period, XRD pattern possessed a sig- nificantly structural mixture of strong ZrN (111), W (110), as well as weak ZrN (220) textures in the multilayered coating. The optimal condition resulted in higher hardness (26 GPa), elastic modulus (310 GPa) and fracture resistance of the coat- ing than other conditions.     

碳纳米管镀铜薄膜的抗菌性研究

本文用离子束辅助沉积（mAD）方法在碳纳米管薄膜表面制备铜薄膜。用琼脂平板法测试了抗菌率，测试菌种为革兰氏阴性大肠杆菌（E．coil）和革兰氏阳性金黄色葡萄球菌（S．aureus）；用扫描电子显微镜（SEM）观测了镀铜碳纳米管薄膜的微观形貌；用能量散射X射线谱（EDX）分析了镀铜碳纳米管薄膜表面元素的原子百分比；用X射线光电子能谱（XPS）分析了镀铜碳纳米管薄膜的表面元素的价态。研究结果表明，镀铜膜碳纳米管薄膜具有优良的抗菌性能，且比在热解碳上镀铜膜样品的抗菌性强。     

离子束辅助沉积制备的铁锆多层膜中的相演化

研究了用氩离子束辅助沉积（ＩＢＡＤ）技术制备的铁／锆多层膜中的微结构演化规律。实验中所使用的氩离子能量范围为４ｋｅＶ到１２ｋｅＶ,束流密度为１２μＡ／ｃｍ＾２。实验结果表明,用ＩＢＡＤ技术右在富锆端制备出完全非晶化的薄膜。对于Ｆｅ（０．５４ｎｍ）／Ｚｒ（４．５ｎｍ）多层膜,随Ａｒ离子能量的增加,在薄膜中还观察到晶态－非晶－亚稳ｆｃｃ相－非晶－晶态的结构转变。对于富铁合金膜,ＩＢＡＤ技术仅能制备部分非晶化的薄膜。